Temperature controlled cases are used for the storage, preservation, and presentation of products, such as food products including perishable meat, dairy, seafood, produce, etc. To facilitate the preservation of the products, temperature controlled cases often include one or more cooling systems for maintaining a display area of the case at a desired temperature. The one or more cooling systems may include one or more cooling elements (e.g., cooling coils, heat exchangers, evaporators, fan-coil units, etc.) through which a coolant or refrigerant is circulated (e.g., a liquid such as a glycol-water mixture, etc.) to provide cooling to an internal cavity of the case. As a result of the cooling, the food products or other stored items are typically maintained in a chilled state.
Lubricants, such as oil, are typically utilized with one or more components of the cooling system. Particularly, a compressor is utilized to pump or circulate the coolant throughout the cooling system. The compressor includes various moving components, such as one or more pistons, that utilize oil for lubrication. However, oil is miscible in the coolant. This miscibility may result in coolant seeping into the compression cylinders of the compressor and at least some oil being circulated throughout the cooling system. Detrimentally, the presence of oil in various locations of the cooling system will inhibit the coolant's heat transfer ability, which may impact performance of the cooling system (e.g., oil may coat the evaporator coils thereby inhibiting heat transfer with the coolant that is flowing therein). Further, if oil is being circulated throughout the cooling system, a potentially insufficient amount of oil for lubrication the compressor may exist. As a result, increased amounts of friction and heat may result in operation of the compressor. Thus, separating the oil from the refrigerant or coolant is beneficial in ensuring efficient operation of the cooling system.